Capping machines typically utilize multiple capping devices, also known as capping heads or headsets, for fitting pre-threaded caps onto containers to secure contents disposed inside the containers. A typical capping device includes a drive member operatively coupled to a drive source such as a drive motor or turret assembly to impart rotation to the drive member. A capper body is coupled to the drive member to rotate with the drive member and slide relative to the drive member. A cap-engaging portion mounts to a bottom of the capper body via a torque dependent clutch such that when the capper body moves downwardly to engage a cap to be threaded onto a container, the clutch limits the amount of torque transmitted to the cap. Often, a spring acts between the cap-engaging portion and the drive member to “soften” the impact of the capper body on the cap. In other words, the spring absorbs the impact of the downward motion of the capping device as the capper body contacts the cap to thread the cap onto the container. Otherwise, the cap may not properly fit on the container.
In some systems, the biasing force provided by the spring is adjustable to adjust the axial force that ultimately acts on the caps. In these systems, a collar with inner threads mates with outer threads on the drive member such that the collar can be threaded or unthreaded on the drive member to move the collar upward or downward, respectfully. The spring, acting between the collar and the capper body, is compressed or decompressed when the collar is threaded or unthreaded on the drive member, respectfully, thereby adjusting the biasing force. To prevent the collar from moving and prevent the biasing force from changing, a setscrew locks the collar in place at a predetermined adjustment position on the drive member. However, the setscrew may be prone to movement during use.
The vibration to the capping device caused by rotation and upward and downward movement associated with repetitive operation may inadvertently release the setscrew from position thereby resulting in unwanted movement of the collar out from the predetermined adjustment position thereby undesirably adjusting the biasing force. Therefore, there is a need in the art for a device that prevents inadvertent adjustment of the biasing force. There is also a need in the art for a device that includes a manner of being able to determine the change in the biasing force during adjustment such that a user can set each of the multiple capping devices in the capping machine to a desired force setting.